Conventionally, a so-called head-up display in, for example, vehicular display devices for automobiles and so on has been known to be directed to improving visibility when a driver sees a display in running. Such head-up display is configured such that a display light emitted from a luminous display installed in a lower portion of a windshield is reflected toward a driver by a thin-layer combiner (reflecting member) formed on a surface of the windshield, or a windshield (reflecting member) having been subjected to combiner processing, whereby the driver overlaps a display image being a virtual image, on front scenery through the windshield to recognize them.
When such arrangement is adopted, the driver can be improved in visibility since movements of line of sight due to alternation of seeing the front through the windshield and visual confirmation of display information are much reduced as compared with the case of seeing a conventional display device (meter device) mounted in a predetermined location on an instrument panel. Also, since the driver can confirm the display image projected onto the windshield without greatly changing an eye's focus from that in the case of seeing the front through the windshield, a period of time required for recognition of display information is shortened and the driver can confirm the display information while seeing a field of front vision, thus enabling enhancing safety in running.
Here, with such head-up display, the driver overlaps the display image being a virtual image, on front scenery through the windshield to recognize them, so that there is a need of modifying a position of the display image to put the same in agreement with the driver's viewpoint.
Generally, a driver selects a position of the display image in agreement with the driver's viewpoint by moving the display image vertically by means of operation of a control switch for rotating movement of a reflector in the display.
Since a display lighted when a driver performs positional adjustment of the display image constitutes a part of a display fully lighted, however, there is involved a problem that when performing positional adjustment of the display image, the driver must adjust a position of the display image while remaining unable to recognize a whole range of the display image and so positional adjustment of the display image is difficult to perform correctly.
JP-A-7-266925 is known to aim at solving such problem and to put a head-up display in a full lighting mode and set its display luminance to a maximum value at the time of vehicle stopping immediately after ignition is made ON.
However, such head-up display is configured such that a display is put in a full lighting mode only immediately after ignition is made ON and when a gear is in a parking state, so that a chance is limitative, in which positional adjustment of a display image can be readily performed. Also, there is involved a problem that visibility cannot be improved in the daytime even when a display has a maximum luminance, and a demand is made for a head-up display capable of readily performing positional adjustment of the display image irrespective of night and day.
In view of such problems, the invention has its object to provide a vehicular display device, in which a chance, in which positional adjustment of a display image is performed, is not limited, and a display image can be readily adjusted to a position in agreement with a driver's viewpoint.